Quick connectors are used widely for connecting tubes serving as automotive fuel lines.
Referring to FIG. 4 showing a representative, known quick connector, the quick connector includes a housing 4 having a connecting part 3 provided with a plurality of annular ridges. The connecting part 3 is forced into a resin tube. A tube 2 to be connected to another tube by the quick connector has an end part provided with an annular ridge 2a on its outer surface.
A retainer 5 retains the tube 2 in a housing 4. The retainer 5 is inserted in the housing 4 through a pipe inlet of the housing 4. When the tube 2 is inserted into the housing 4 after inserting the retainer 5 into the housing 4, end edges of tongues 6 engage with the annular ridge 2a to restrain the tube 2 from falling off the housing 4. The quick connector can easily connect the tubes without using any fasteners, such as bolts.
A quick connector of this type to be used in an automotive fuel supply system is required to have a particularly reliable sealing capacity capable of surely preventing the leakage of the fuel from the quick connector. Recently, sever environmental regulations have been enforced to place restrictions on the diffusion of the fuel leaked through connectors into the atmosphere.
A quick connector similar to the quick connector shown in FIG. 4 and proposed in, for example, JP 2003-287180 A has enhanced sealing construction.
In this previously proposed quick connector, a housing is provided with an annular protrusion at a position corresponding to that of a spacer 8 of the quick connector shown in FIG. 4, sealing member holding spaces are formed on the opposite sides of the annular protrusion, respectively, and annular sealing members respectively having different sealing abilities are placed in the sealing member holding spaces, respectively.
Patent document 1: JP 2003-287180 A